Duplicating process



3,049,994 DUPLICATING PROCESS Walter A. Raczynski, Park Ridge, Richard E. Thomas, Chicago, and Allen E. Uhl, Palatine, 111., assignors t Ditto, Incorporated, Chicago, 111., a corporation of Delaware N0 Drawing. Filed Oct. 19, 1959, Ser. No. 847,046 Claims. (Cl. 101-4495) The present invention relates to processes for duplicating copy by means of the transfer of dye from a master. The most common forms of such copy duplication are known as a spirit transfer process and the gelatin transfer process. More specifically, the present invention relates to methods and means for fixing the dyes in the duplicated copy against fading and smearing.

In the preparation of copies according to both the spirit process and the gelatin process, a base sheet, commonly known as a carbon, is employed. This base sheet is coated on one side with the composition including dyes generally soluble in alcohol and water. The carbon employed for the spirit process is identified as a spirit carbon and the carbon utilized for the gelatin process is identified as a gelatin carbon.

The spirit carbon is combined with a master paper overlying the composition coating including the dye so that by marking, pressing or otherwise applying pressure to the exposed surface of a master paper, a transfer of the dye composition from that base sheet to the master paper is accomplished. Thus by placing such an assembly in a typewriter with the master paper arranged to receive the type impressions, a reverse reading transfer image is created on the backside of the master paper in accordance with the typed copy. A similar reverse reading transfer image can be created on the back of the master paper through use of a pen, pencil or marking stick. The master paper, with the reverse reading image, is disassociated from the base sheet and becomes what is commonly called the imaged master. This imaged master can then be used with a spirit duplicator machine for achieving a multiplicity of direct reading copies. In this machine, advantage is taken of the fact that the dyes are soluble in alcohol and water.

Specifically, in the spirit duplicating machine the image master is placed in the machine with its imaged side exposed and a supply of copy paper on which it is desired to provide duplications of the imaged material is positioned for individual feeding. The machine also includes a solvent reservoir containing a mixture of primary and secondary aliphatic alcohols which is applied by means of a wick or a brush to the copy paper as a part of each duplicating cycle. During each duplicating cycle, the copy paper, moistened with the alcohol solvent, comes into contact with the imaged master for but a brief moment causing a controlled amount or increment of the dye composition to be dissolved from the imaged master and onto the copy sheet. Thereafter, the copy sheet is passed from the imaged master, the alcohol solvent evaporates and there is created on the copy sheet a direct impression exactly as imparted by the imaged master, but in this instance, direct reading. This duplication cycle is repeated with other sheets of copy paper until the dye on the master is completely depleted.

This spirit process of duplication has found widespread use and popularity because of its simplicity, ease, and facility with which masters can be made and the minimum amount of equipment necessary for producing the duplications. But this success has not been without limitation inasmuch as the dyes and dye compositions heretofore employed have had a tendency to become illegible either asby fading from sunlight, for example, or running or process.

3,949,994 Patented Aug. 21, 1962 blurring in the presence of cutting oils, moisture, and other adverse conditions. Considerable research has been done on this problem, but to date no process has been developed for preparing a fixed duplicating copy that is both effective and at the same time is simple to use and inexpensive.

It is a general object of the present invention to provide a new and improved inexpensive method of preparing duplicating copy that is stabilized against fading and against smearing and blurring.

It is a further object of the invention to provide a new and improved chemical process for preparing duplicating copy which will stabilize the copy from fading or running and which will, at the same time, not attack or corrode the metallic duplicating equipment.

It is a further object of the invention to provide a chemical composition which can be utilized with the duplicating process, in the duplicating process or after the duplicating process is completed for purposes of stabilizing the copy against fading and blurring.

A more specific object of the invention is to provide a chemical stabilizer and a carrier therefor which will react with the basic dyes employed in the transfer processes for fixing copy so produced against fading and smearing.

An additional object of the invention is to provide a new and improved solvent composition for use in the transfer processes which will react with basic dyes of the kind including diphenylmethane, triphenylmethane, vxanthene and azine for transferring an increment of the dye to copy sheets and for rendering such dyes substantially insoluble.

A further object of the invention is to provide a new and improved solvent which may be used directly in the conventional transfer process or as a post treatment step to the conventional method of producing duplicating copies which will render the conventional triphenylmethane dyes substantially insoluble.

A further object of the invention is to provide an improved copy paper for use in the transfer processes which is treated in a manner so as to react with the conventional triphenylmethane dyes in the duplicating method thereby fixing the dyes against fading and smearing.

Another object of the invention is to provide an adhesive type carrier with a dye stabilizer compound which maybe used to adhere a duplicated label to a package and also as a protective coating for the label that also reacts with and stabilizes the dye.

Further objects and features of the invention pertain to the particular methods and arrangements whereby the above and other identified objects of the invention are attained.

The invention, both as to its composition andmethod of use and application, will be better understood by reference to the following disclosure.

It has been known that the use of heteropolyacids and salts in conjunction with basic dyes results in an extremely insoluble complex. Although only the most commonly used of the dyes, triphenylmethane, is specifically referred to in the following explanations, it is understood that this is merely for the sake of brevity and that the other basic dyes, diphenylmethane, xanthene and azine are necessarily included with each reference. It has been the experience that reaction products of basic dyes with such acids are not suitable for use in the spirit The dye impressions on'the image master become case-hardened so that the image is unavailable for producing copies. Obviously, this characteristic gives the dye composition the insoluble or case-hardened shell and also makes the dye transferred to the copy'relatively insoluble. Thus the copies produced from the reaction of heteropolyaoids and triphenylmethane dyes, for example, might be expected to provide fade proof and smear-proof copy. However, a dilemma is reached in that the reaction which will produce the desirable insolubility characteristic on the copy also produces the same characteristic on the image master, so that the process as known is not usable in a multiple copy duplicating process. However, careful investigation indicates that this dilemma is not without a solution.

Giving specific consideration to the heteropolyacids and to the salts of the heteropolyacids of interest, they are derived from complex phospho and silico compounds of tungsten and molybdenum which are classified generally in the groups of complex acids, mixed complex acids, and the alkali metal salts of complex acids. The complex acids, properly referred to as heteropolyacids, are the product of a reaction between a polyacid formed from the condensation of tungsten or molybdenum oxygen radicals, and the orthophosphoric acid or orthosillicic acids. A number of complex acids may be formed from this reaction, each known according to the mole ratio of phosphorous pentoxide P or silicon dioxide SiO to tungsten trioxide W0 or molybdenum trioxide M00 Thus phosphomolybdic acid 3 P205 XHzO has a ratio of P 0 to M00 of 1 to 24 and is known as the phospho-24-molybdic acid, and the silico tungstic acid 3-H O'SiO -24\VO -XH O has a ratio of SiO to W0 of l to 24 and is known 'as silico-24-tungstic acid. Other complex acids exist in mole ratios of P 0 or SiO to W0 or M00 of l to 18 and l to 12 The mixed complex acids are acids that include polyacids of both tungsten and molybdenum oxides and are, for example, phosphotungstomolybdic and silicotungstomolybdic acids. A specific phosphotungstornolybdic acid is phospho-lS tungstic-6 molybdic acid where the ratio of P 0 to the combined oxides of tungsten and molybdenum is l to 24. A specific silicotungstomolybdic acid is silico-lS tungstic-6 molybdic acid 3H O'SlO '18WO 6MOO where the ratio of SiO; to the combined oxides of tungsten and molybdenum is l to 24.

The salts of these lieteropolyacids comprise the third group mentioned above. As with the acids, these salts exist in definite mole ratios of P 0 or SiO to the molybdic and tungstic oxides. Research on these complex acids, mixed complex acids and their salts have indicated certain specific combinations of the heteropolyacids, certain alkali salts thereof and admixtures of these products in given proportions with a carrier material which will react with triphenylmethane dyes to fix the dye and at the same time not otherwise deprecate the carrier, the equipment used or the copy. Certain formulations have been found to be useful as a solvent in the duplicating process, other formulations have been found suitable as treated copy paper for the duplicating process and as coating materials for protecting the surface of the duplicated copy.

It has been discovered that good fade inhibition can be obtained by using the sodium salt of phospho-24- tungstate 3(Na- O)-P O -24-WO -X[-I O, ammonium phospho-l S-tungstate 3 (NI-I 2 0- P 0 18 -WO XH O and potassium phospho-lS-tungstate 3 K 0 -P O l8WO Further, good fade inhibition was obtained by using ammonium phospho-24-tungstate, ammonium phospho- 24 molybdate, potassium phospho-24 tungstate, and potassium phospho-24 molybdate.

In all of these salts it was found that the ratio of P 0 to M00 or W0 would give good fade inhibition characteristic when the mole relationship was as low as 1 to 12.

Further investigation revealed that by blending a salt such as ammonium phospho-24 tungstate with an acid, such as silico-l2 tungstate acid in the duplicating solvent mixture of primary alcohols, a further improvement in the fade resistance of the produced copy was experienced. This admixture produced better results than the use of the individual alkali salt in the solvent mixture or the use of the individual heteropolyacid in the solvent mixture.

While the above described compositions have proved useful in producing fixed copy or copy exhibiting good characteristics of fade inhibition, and so in that sense is successful for the stated purpose, it was found that in the solvent mixture, the composition might attack metals found in the cans for transporting the solvent and in the metal parts of the duplicator. Specifically, in the preparation of the heteropolyacid or the alkali metal salt of the acid, the product produced is normally extremely acidic, such that in solution, the pH was more acidic than a pH 5, and usually ranging from a pH 1 to pH 4. The use of the polyacids, the heteropolyacids and the alkali metal salts of the heteropolyacids or their mixtures in a solution which is more acidic than a pH of 5, results in corrosive attack of the materials used in packaging and of the duplicating equipment. Over a period of a few months, a decrease in the antifade effectiveness of the untreated fiuid is experienced due to the contamination from heavy metals found in the cans and metal parts of the duplicator. The clear solution turns dark and usually develops strong odors. Thus the untreated fluid can cause irreparable dam-age to the parts of a duplicator machine.

It has been found that these difiiculties can be overcome and that the antifade properties of the alkali salt or the heteropolyacid in solution can be retained by passing the solution thereof through an ion exchange Resin column until a pH of 5.0-6.5 is achieved.

Giving specific consideration to the preferred compositions to be employed in a duplicating process solvent, for example, the preferred materials have been found to be the alkali metal salt of phosphotungstic acid, phosphomolybdic acid, silicotungstic acid or silicomolybdic acid, or the sodium salt of the mixed condensation of acids such as phosphotungstomolybdic acid or silicotungstomolybdic acid. For use of these preferred materials in solvents generally employed in the duplicating processes, which solvents are essentially primary and secondary aliphatic alcohols or alcohol-water mixtures, it is important that the selected preferred materials be soluble in the solvent. Of the heteropolyacid salts listed above, the sodium, potassium and ammonium salts all have been found soluble to an extent which makes them operable. Such a salt has been found to be eifective for producing fade inhibition when added in amounts as small as 0.2% by weight of the total solvent mixture and up to as much as 5% by weight of the total solvent mixture.

The solvent thus formulated may then be used in the spirit duplicating machine in the manner as described above. In this method of application that is simultane ous with the duplicating process there is no loss of copy intensity, reproductive life of the master or any discoloration or tinting of the copy. The copy so treated is fixed to withstand exposures to sunlight, moisture and the effects of printing oils, and it may be immersed in water or placed under running water with much reduced running or smearing effects.

It has been found that when copies which have been thus prepared are subjected to a post-treatment with a fluid such as the alcohol type solvent containing the heteropolyacids and their salts, as described above, the fade resistance is increased to such an extent that the copy may be considered for all practical purposes to be permanent. Utilizing this observation, it has been found possible to use the copy produced according to the first duplicating process in a subsequent or second duplicating process thereby adding additional information from another master and all without the effect of smearing, blurring or bleaching out the original dye impression during the subsequent duplicating process.

Further to the above described advantages of using the materials of the invention including the heteropolyacids and their salts in a duplicating process solvent, it has been found that the copy paper used in this spirit process may be manufactured to include the described group of stabilizing compounds. Thus during the manufacture of paper, the heteropolyacids, the salts of the heteropolyacids or the mixtures thereof may be added to the heaters and incorporated in the formulation of the batch. Paper so prepared when moistened with the conventional solvent during the duplicating process causes a reaction with the triphenyl-methane dyes thereby to produce stabilization of the dye.

Where it is desired to get the highest degree of stabilized copy in a duplicating process employing triphenyl-methane dyes, it is preferred to utilize copy paper treated with stabilizing compounds as described, with a duplicating solvent including the stabilizing compounds, and then applying to the duplicated copy the post-treatment stabilizing application as described.

Primary attention herein has been directed to the spirit duplicating process. However, it is to be understood that the copies produced by the gelatin reproduction process can also be made to be fade-proof and stable by utilizing the post-treatment process described above. This is accomplished by applying to the copy after it has been duplicated, a film of the solvent containing the stabilizing compound. This post-treatment causes the dye to react with the heteropolyacids or their soluble salts to form complexes which are fade-proof and less soluble in water and oils.

From the foregoing disclosure, it is obvious that the stabilizing compounds of the heteropolyacids and salts of heteropolyacids and mixtures thereof are adaptable to any number of circumstances for fixing copy produced from triphenylmethane dyes. Specifically, while in the foregoing examples the carrier for the stabilizing compounds has been described in one instance to be primary and secondary aliphatic alcohols in Water, and in another example, the carrier is described as being paper pulp, it is understood that various other types of carriers may be developed for specific usages. For example, the stabilizing compound might be carried in a lacquer for coating a prepared duplicating copy which would, in reaction with the triphenylmethane dye, fix the dye against fading and at the same time cover the sheet with a moisture proof coating. This might be employed with a label prepared by the duplicating process for example. In one specific use, an alkali salt of the heteropolyacids is mixed with a particular label adhesive mixture which could be utilized with a label produced by the duplicating process on the backside for joining the label to a container and also could be applied to the front face for reaction with the triphenylmethane dye thereby to fix the dye and at the same time provide a protective coating for the label. A label adhesive carrier found to be most suitable for this use is a casein-starch-gelatin mixture.

To show clearly the advantages derived from treatment of copy in accordance with the described processes, reference is made to the following chart showing the fade resistance protection afforded a copy by the various types of treatments described.

Copy Treatment Visible Life Conventional paper and fiuidno post treatment Conventional paper and fluid-post treatment Conventional paper and special fluidno post treatment Special paper, conventional fluid-no post treatment Special paper and fluid-no post treatment Special paper and fluidpost treatment other differently treated copies is recited in terms of multiples of the selected unity life period. It is obvious that treatment in accordance with the terms of this invention does. more than just extend the legibility life of the copies, but actually multiplies that legibility life. In terms of normal usage, th's multiplication amounts to efiective permanence.

For purposes of rendering evidence of the best modes of practicing the present invention, and not for purposes of introducing limitation, the following examples of solvents employable as a duplicating process and/or as a post-treatment fluid, are submitted.

EXAMPLE NO. I

Weight percent Primary or secondary aliphatic alcohols 1 -90 Water 5-10 3(Na O)-P O -24WO -XH O 0.2-5.0

EXAMPLE NO. 11

Primary or secondary aliphatic alcohols 85-90 Water 5-10 3(Na O)-P O -24MoO -XH O 0.2-5.0

EXAMPLE NO. 111

Primary or secondary aliphatic alcohols 85-90 Water 5-10 3-H O-P O -24WO -XH O 0.2-5.0

EXAMPLE NO. IV

Primary or secondary aliphatic alcohols 85-90 Water 5-10 3(Na O)-SiO -12MoO -XH O 0.2-5.0

EXAMPLE NO. V

Primary or secondary aliphatic alcohols 85-90 Water 5-10 3(H O)-SiO -l8MoO -XH O 02-50 EXAMPLE NO. VI

Primary or secondary aliphatic alcohols 85-90 Water 5-10 3 H o -1 o -iswo- -eMoo 0.2-5

EXAMPLE NO. VII

Primary or secondary aliphatic alcohols 85-90 Water 5-10 3(H O)-SiO -12WO -XH O 0.1-2.5 smrip o-r o -mwo -xi o 0.1-2.5

1 Solvent% to 99.8%.

An example of a mixture found to be suitable in the production of paper is as follows:

To the beaters in the paper making process is added 3(Na O)SiO -24WO -H O ranging from l%5% by weight of the batch.

An example of a mixture found to be suitable for con oint use as an adhesive and stabilizer-coating is as follows:

Percent Label adhesive mixture casein-starch-gelatinna 50-60 Water 35-48.8 3(Na O)-P O -24WO -XH O 0.2-5.0

It is understood that the principles of the present invention as disclosed herein can be variously employed by those skilled in the art and it is intended to cover in the appended claims all such variations as fall within the true spirit and scope of the invention.

What is claimed is:

1. A composition for reaction with the basic dyes, comprised of a carrier, 95% to 99.8% by weight, and an alkali metal salt of an acid selected from the group consisting of phosphotungs-tic, phosphomolybdic, silicotungstic, silicomolybdic, phosphotungstomolybdic, silicotung stomolybdic and combinations thereof, wherein the mole ratios of the oxides of phosphorous andof silicone to the oxides of molybdenum and tungsten is in a range between 1 to 12 and 1 to 24; said salt comprising from 0.2% to 5.0% by weight of said composition and said composition having. a pH in the range from 5.0 to 6.5.

'2. The composition asset forth in claim 1, wherein said carrier is a paper-pulp mixture.

3. The composition as set forth in claim 1, wherein said carrier is a mixture of casein, starch and gelatin.

4. A composition for reaction with the basic dyes comprised of a carrier, 95% to 99.8% by weight, and the sodium salt of an acid selected from the group consisting of phosphotungstic, phosphomolybdic, silicotungstic, silicornolybdic, phosphotungstomolybdic and silicotungstomolybdic, said salt comprising from 0.2% to 5.0% by weight of said composition and the pH of the composition is in the range from .0 to 6.5.

5. The composition set forth in claim 4, wherein said sodium salt is sodium phosphotungstate.

6. The composition set forth in claim 4, wherein said sodium salt is sodium silicotungstate.

7. A process for reproducing stabilized copies from impressions of the basic dyes comprising the steps of: preparing a dye impression of the matter to be duplicated; subjecting said dye impression to a composition for dissolving an incremental portion thereof said composition having a pH of 5.0 to 6.5, and comprised of a solvent and an alkali metal salt from 0.2% to 5% by weight of said composition, said salt being selected from the group of acids consisting of: phosphotungstic, phosphomolybdic, silicotungstic, silicomolybdic, phosphotungstomolybdic, and silicotungstomolybdic, and combinations thereof; wherein the mole ratios of the oxides of phosphorous and of silicone to the oxides of molybdenum and tungsten is in a range between 1 to 12 and 1 to 24; and transferring the dissolved incremental portion of said dye impressions to a copy paper; drying said dissolved transferred incremental dye impression on said paper; applying to the transferred dye impression on said paper a fixing composition of the same formulation of said composition; and drying '8 said fixing composition whereby said dye impression on said copy is fixed against fading and smearing.

8. The method set forth in claim 7, wherein said composition is comprised of primary and secondary aliphatic alcohols.

9. The method set forth in claim 7, wherein said copy paper includes therein the alkali metal salt of an acid selected from the class consisting of phosphotungstic, phosphornolybdic, silicotungstic, silicomolybdic, phosphotungstomolybdic, and silicotungstomolybdic, and combinations thereof; wherein the mole ratios of the oxides of phosphorous and of silicone to the oxides of molybdenum and tungsten is in the range between 1 to 12 and 1 to 24.

10. The process set forth in claim 7, wherein said fixing composition is comprised of casein, starch, gelatin, and water, to 99.8% by Weight, and an alkali metal salt, from 0.2% to 5.0% by Weight of an acid selected from the class consisting of phosphotungstic, phosphomolybdic, silicotungstic, silicomolybdic, phosphotungstomolybdic, and silicotungstomolybdic and combinations thereof; wherein the mole ratios of the oxides of phosphorous and of silicone to the oxides of molybdenum and tungsten is between the range of 1 to 12 and l to 24; and the pH of the composition is within the range from 5.0 to 6.5.

References Cited in the file of this patent UNITED STATES PATENTS 1,923,625 Jackson Aug. 22, 1933 2,088,417 Hoskins July 27, 1937 2,163,934 Collins June 27, 1939 OTHER REFERENCES Mellor: A Comprehensive Treatise on Inorganic and Theoretical Chemistry, vol. XI, 1931 (p. 863 relied on. Copy available in Scientific Library). 

1. A COMPOSITION FOR REACTION WITH THE BASIC DYES, COMPRISED OF A CARRIER, 95% TO 99.8% BY WEIGHT, AND AN ALKALI METAL SALT OF AN ACID SELECTED FROM THE GROUP CONSISTING OF PHOSPHOTUNGSTIC PHOSPHOMOLYBDIC, SILICOTUNGSTIC, SILICOMOLYBDIC, PHOSPHOTUNGSTOMOLYBDIC, SILICONTUNGSTOMOLYBDIC AND COMBINATIONS THEREOF, WHEREIN THE MOLE RATIOS OF THE OXIDES OF PHOSPHORUS AND OF SILICONE TO THE OXIDES OF MOLYBDENUM AND TUNGSTEN IS IN THE RANGE BETWEEN 1 TO 12 AND 1 TO 24; SAID SALT COMPRISING FROM 0.2% TO 5.0% BY WEIGHT OF SAID COMPOSITION AND SAID COMPOSITION HAVING A PH IN THE RANGE FROM 5.0 TO 6.5. 